The invention relates to a television circuit arrangement for determining in a video signal, frame periods comprising two field periods, whereby a video signal comprising a picture signal is present at an input terminal and originates from a signal source for supplying a picture signal repeated in cycles of two successive field periods and with a possible change of picture content.
Such a television circuit arrangement can be used with a signal source described in U.S. Pat. No. 3,886,589 which is, for example, in the form of a so-called "field skip" signal storage and display device or of a cine-film television converter. With the use of such a storage and display device, the picture signals are stored only every other field period. When the stored signal is produced by the device, the stored information is repeated once in the next field period. Thus, a television picture signal is obtained repreated in cycles of two successive field periods and, possibly, varying therebetween in a stepwise manner as caused by picture content changes.
In the case of the cine-film television converter as the signal source, the information associated with one cine-film picture does not occur in one field period of the picture signal, but it occurs repeatedly in the next field period. Further, abrupt variations between the cine-film pictures frequently occur due to the film assembly of separately recorded scenes. Also in this case, the result is that the signal source supplies the television picture signal repeated in cycles of two successive field periods and, possibly, varying therebetween in a stepwise manner.